This invention relates generally to dishwashers, and, more particularly, to dishwasher system fluid circulation assemblies.
Known dishwasher systems include a main pump assembly and a drain pump assembly for circulating and draining wash fluid within a wash chamber located in a cabinet housing. The main pump assembly feeds washing fluid to various spray arm assemblies for generating washing sprays or jets on dishwasher items loaded into one or more dishwasher racks disposed in the wash chamber. Fluid sprayed onto the dishwasher items is collected in a sump located in a lower portion of the wash chamber, and water entering the sump is filtered through one or more coarse filters to remove soil and sediment from the washing fluid. At least some dishwasher systems further include a fine filter system in flow communication with the main pump assembly to remove soil and sediment of a smaller size than those filtered by the coarse filters. The main pump assembly draws wash fluid from the sump to re-circulate in the wash chamber, and the coarse and fine filters are used to continuously filter the water in the sump during the re-circulation process.
At least some known dishwasher systems include a plurality of openings in the tub bottom for feeding wash fluid to lower spray arm assemblies, upper spray arm assemblies, and fine filter systems. Each opening in the tub bottom, however, presents a potential leak in the system.
In an exemplary embodiment of the invention, a dishwasher spray arm hub assembly includes a hub having a first central bore extending therethrough and a conduit feed extending therefrom. The conduit feed is in flow communication with the central bore and a venturi insert is disposed in the hub central bore. The venturi insert also includes a second central bore extending therethrough. The first bore and the second bore together form a fluid bypass channel in flow communication with the conduit feed. Therefore, a lower spray arm assembly and a spray arm conduit for upper spray arm assemblies may be simultaneously fed through the hub assembly. Consequently, the hub assembly requires only one hole through the tub to feed wash fluid into a wash chamber. Potential leaks in the system attributable to fluid feeds through the tub are therefore minimized while minimizing the height of the spray arm assembly in the tub, thereby optimizing useful tub volume.
More specifically, the spray arm hub assembly includes a longitudinally extending hub base, and the conduit feed extends laterally from the hub base for coupling to an upper spray arm conduit. The conduit feed includes a fine filter inlet passage to establish flow communication with a fine filter assembly. Indirect feeding of the fine filter assembly lowers an operating pressure in the fine filter assembly to improve fine filter performance and reduce instances of premature draining of the tub due to pressure conditions in the fine filter assembly.
A spray arm hub assembly is therefore provided that simplifies dishwasher assembly, and reduces potential leaks in the system without compromising useful tub volume.